Contraception: Many Options

About half of all pregnancies in this country are unplanned, according to the American College of Obstetricians and Gynecologists. For a woman who wants to plan when she becomes pregnant, however, there are many choices.

Contraception -- also called birth control -- refers to methods or devices that prevent pregnancy either by preventing a woman’s egg from being fertilized by sperm or by preventing a fertilized egg from being implanted in the uterus.

Which method or methods you choose depends on several factors, including your menstrual period, any existing health conditions, convenience of the contraceptive and its ease of use, risk factors, side effects and cost. Your health care provider can help you determine the method that's appropriate for you.

Keep in mind that you may change your contraception method as the circumstances of your life change. When choosing a method, you should consider how often you have sex, if you are in a monogamous relationship, if you are willing to plan for sex or want a method that doesn't depend on planning, and how will you are to track your fertile days or take a pill every day. To work effectively, a contraceptive method must be used correctly.

Below is a general description of the most common categories of contraception methods approved by the U.S. Food and Drug Administration (FDA).

Hormonal methods

These methods, available only by prescription, use hormones similar to estrogen and progestin, the hormones naturally produced by a woman’s body. The hormones prevent ovulation -- when the ovaries release an egg. Hormonal methods offer continuous contraception, but they do not protect you against sexually transmitted infections (STIs). Women who have had a stroke, have liver disease, breast cancer or problems with blood clotting should not use these methods.

Birth control pills/oral contraceptives

Some birth control pills contain both estrogen and progestin (combination pill); others have only progestin (progestin-only mini-pill). A chewable form of the combination pill is available.

Combination pills prevent ovulation. These pills are taken daily, regardless of how often a woman has intercourse. Women using the chewable tablet must drink eight ounces of liquid immediately after taking it. The usual method of taking birth control pills allows a woman to have a predictable period every four weeks. A woman can also choose a schedule that instead allows her to have a menstrual period every 13 weeks. This must be under the direction of a health care provider, however. The FDA says birth control pills are 99 to 98 percent effective when prescribed and taken correctly. Possible side effects of the combination pill include dizziness; nausea; and changes in menstruation, mood or weight. Rarely, cardiovascular disease can result; this can include high blood pressure, blood clots, heart attack and strokes. Women who smoke and are older than age 35 should not use these pills.

Progestin-only pills prevent pregnancy by thickening cervical mucus to stop the sperm from reaching the egg. The FDA says these are 98 percent effective when prescribed and taken correctly. They must be taken on a daily schedule, regardless of how often a woman has intercourse. Possible side effects of the progestin-only pill include irregular bleeding, weight gain and breast tenderness. These pills also offer less protection against ectopic pregnancy.

Patch

This is a skin patch that releases estrogen and progestin directly into the bloodstream. It is worn on the lower abdomen, buttocks or upper body, but not on the breasts. A new patch is applied once a week for three weeks. It is not worn during the fourth week to allow a menstrual period. The FDA says it is 98 percent effective, but it may be less effective in women who weigh more than 198 pounds. Patches contain more estrogen than birth control pills do. Possible side effects are similar to those of the combination oral contraceptive pill, but the risk for blood clots may be greater with the patch because it contains more estrogen. Other factors that put women at risk for blood clots are smoking, obesity, inactivity and surgery; using the patch with these risks increases them.

Vaginal contraceptive ring (NuvaRing)

This is a flexible ring about two inches in diameter that is inserted by a woman into her vagina. There, it releases progestin and estrogen. The ring remains in place for three weeks, and is then removed for one week to allow a menstrual period. The FDA says it is 99 to 98 percent effective when used correctly. If the ring is expelled from the vagina and remains out for three or more hours, another method of birth control must be used until a new ring has been in place for seven days. Possible side effects include vaginal discharge, vaginitis, irritation and side effects similar to those of the combination oral contraceptive pill.

Injections

Two types of hormone injections are available:

Depo-Provera is a form of the hormone progestin. Injected once every three months, it prevents pregnancy in three ways: It prevents ovulation, stops the sperm from reaching the egg, and prevents the fertilized egg from implanting in the uterus. The FDA says it is 99 percent effective. Depo-Provera usually stops a woman's menstrual periods. Periods resume when a woman stops using this contraceptive. Possible side effects of Depo-Provera include irregular bleeding, weight gain, breast tenderness and headaches.

Lunelle is a form of progestin and estrogen. It is injected once a month. The FDA says it is 99 percent effective. Possible side effects include changes in menstrual cycle, weight gain and side effects similar to those of the combination oral contraceptive pill.

Implanted contraception

Currently, only one form of implantable contraception is available, Implanon. Approved in 2006, it consists of a small sticklike rod placed beneath the skin of the inner upper arm. The rod slowly releases etonogestrel, a hormone similar to progesterone. Effective for three years, Implanon must be inserted and removed by a health care provider using a minor outpatient surgical procedure. Possible side effects include irregular, missed or painful periods, weight gain, acne, headaches, breast tenderness, hair loss, changes in mood and/or libido, abdominal pain and an increase in blood pressure. It is important to have regular follow-up appointments with your health care provider.

Although some women may still be using the original implantable contraception, Norplant I, it is no longer available to new users. It was discontinued in 2002. If you have a Norplant I implant, you should talk to your health care provider about other options when your implant expires.

Intrauterine device (IUD)

An IUD is a T-shaped plastic frame with thread attached that is inserted into the uterus by a health care provider. IUDs, which offer continuous contraception, come in three types. One type, ParaGuard, has copper on the plastic frame; another type, Mirena, contains a form of the hormone progesterone called levonorgestrel; the third type, Progestasert, contains progestin. An IUD prevents sperm from entering the fallopian tubes, the places where eggs are fertilized. If a sperm does reach an egg, an IUD prevents the fertilized egg from implanting in the uterus. IUDs are 98 to 99 percent effective. After insertion, the copper IUD can remain in place up to 10 years; the Mirena IUD, for five years; and the Progestasert IUD, for one year. All IUDs must be removed by a health care provider. IUDs do not protect you from STIs. Possible side effects include cramps, bleeding, pelvic inflammatory disease, infertility and perforation of uterus.

Barrier devices

Barrier devices come in many forms. Unlike hormonal methods or the IUD, which work continuously to provide protection against pregnancy, a barrier device is used only when a woman has intercourse. A plus is that barrier devices are usually cheaper. A drawback is the need to plan for sex so that you have a barrier device with you. The diaphragm, cervical cap and shield may be difficult for some women to insert properly. Some barrier methods can help protect you against STIs.

Female condom

The female condom is a lubricated, loose-fitting polyurethane pouch that is inserted into the vagina. It surrounds the penis during intercourse and serves as a lining to physically protect the vagina and cervix from infections and trap sperm to prevent pregnancy. Available over the counter (OTC), the condom has a closed end and an open end, with flexible rings at both ends. The closed end is inserted into the vagina, and the ring holds it in place over the cervix. The female condom can be inserted up to 24 hours before intercourse, and can only be used once. Although it comes with lubrication, more may be needed during intercourse. The female condom is stronger than a male condom and should never be used with a male condom. It is between 80 and 95 percent effective in preventing pregnancy and may protect from fluid-transmitted and some virally transmitted STIs.

Male condom

The male condom is a lubricated sheath that is put on an erect penis prior to entry into the vagina. The male condom traps sperm and forms a physical barrier between the vagina and penis. Because of the barrier, it offers protection from fluid-transmitted and some virally transmitted STIs. Available OTC, male condoms can be made of three different substances. Latex is the most common and protects from STIs. The other two substances are polyurethane and animal membrane, which does not protect from you from STIs; do not use animal membrane condoms. Male condoms come in different sizes; a correct size is important to assure protection. When the condom is on the erect penis, there should be room at the tip to allow sperm and fluids. If more lubrication is needed, use only water-based lubricants with latex condoms. A male condom can only be used once. After intercourse, the male should withdraw the penis while holding onto the base of the condom to prevent it from coming off. Used correctly, male condoms are 85 to 89 percent effective in preventing pregnancy. Using a vaginal spermicide with a condom increases its effectiveness. Using a condom that is too old (past its expiration date), brittle, torn or damaged, or put on incorrectly will not protect you from pregnancy or infections.

Diaphragm, cervical cap and shield

These reusable barrier methods of birth control block sperm from entering the cervix and reaching the egg. They are made of latex, and all require a prescription. The diaphragm is a shallow cup; the cap is smaller and thimble-shaped with a strap to aid removal; the shield is a cup-shaped device that covers the cervix, but not a tightly as does the cap. The diaphragm and cap come in various sizes; a health care provider determines what size you need. Having a child or gaining/losing a significant amount of weight can affect how these fit and may mean you need a different size. The shield comes in only one size. All three methods are used with a spermicide to kill sperm. When used correctly, the cervical cap is 84 to 91 percent effective in preventing pregnancy; the diaphragm is 84 to 94 percent effective; and the cervical shield is 85 percent effective. All must be inserted before sex and be left in place for six to eight hours after sex. The diaphragm must be removed by 24 hours after intercourse to avoid the risk for toxic shock syndrome; the cap and shield must be removed 48 hours after intercourse, also to avoid the risk for toxic shock. Other possible side effects of the cap and shield include urinary tract and vaginal infections. The diaphragm, when used with a spermicide, can protect against some STIs. The cap and shield do not provide much protection against STIs.

Contraceptive sponge

This barrier method of birth control is a soft, disk-shaped device with a loop for removal. Available OTC, it is made of polyurethane foam and contains the spermicide nonoxynol-9. Prior to intercourse, the sponge is moistened with water and inserted (loop side down) to cover the cervix. It can be put in up to 24 hours before sex. It must be left in for at least six hours after intercourse. It is 84 to 91 percent effective, if used correctly. It is effective for more than one act of intercourse for up to 24 hours. It must be removed within 30 hours of being inserted. If left in longer, there is a risk of getting toxic shock syndrome. The sponge does not protect against STIs.

Emergency contraception

Emergency contraception keeps a woman from becoming pregnant. If a woman is already pregnant, emergency contraception will not work. These are the circumstances in which emergency contraception methods can be used:

A contraceptive method fails, such a condom breaking or coming off during sex

No contraception was used when you had sex

You were forced to have sex

You missed two or more birth control pills in a row

You were late getting your Depo-Provera or Lunelle shot

Emergency contraception works by preventing the egg from leaving the ovary, by preventing the egg from being fertilized, or by preventing a fertilized egg from implanting in the uterus. It does not affect a woman’s future pregnancies. If you think you might need emergency contraception in the future, you can talk with your health care provider about getting emergency contraceptive pills (ECPs) at your next regular exam.

If you do not have a menstrual period three weeks after you take ECPs, or if you think you might be pregnant after taking ECPs, get a pregnancy test to make sure you're not pregnant.

Plan B

Plan B is the only ECP approved by the FDA for emergency contraception. It is available as an over-the-counter option for women ages 18 and older; it is available for girls 17 and under only by prescription. Plan B is often referred to as the "morning-after pill." It contains the progestin levonorgestrel, which is found in prescription birth control pills but in a lower dose. Two pills are taken, either together or one within three days after unprotected sex and the second 12 hours later. When used as directed, Plan B effectively and safely prevents pregnancy 80 to 99 percent of the time. Possible side effects include nausea, vomiting, abdominal pain, fatigue and headache. Taking both pills at the same time will not increase your chances of having these side effects. If you throw up after taking ECPs, call your doctor or pharmacist. Plan B does not protect against STIs. Another ECP, Preven, was withdrawn from the market in 2004.

Higher dose of birth control pills

Taken at a higher dose, some combined estrogen and progestin birth control pills can be used as emergency contraception. Different brands of combined birth control pills have different doses of these hormones, and the number of pills in a dose is different for each brand. Not all brands can be used for emergency contraception. For more information on birth control pills that can be used for emergency contraception go to Not-2-late.com (http://ec.princeton.edu/questions/dose.html). In general, the pills are taken in two doses, one dose right away and the second dose 12 hours later. Always use the same brand for both doses. Combined estrogen and progestin pills are 75 to 80 percent effective when taken this way. Some women feel sick and throw up after taking them. If you throw up after within one hour after taking ECPs, call your doctor or pharmacist.

IUD

A copper IUD inserted within seven days of unprotected sex can prevent 99 percent of pregnancies. It can prevent the sperm from fertilizing the egg or prevent a fertilized egg from implanting in the uterus. It can remain in place and be used as a method of birth control, or it can be removed after the next normal menstrual period.

Abortion pill

The abortion pill RU-486 (mifepristone) works after a woman becomes pregnant, when a fertilized egg has attached to the uterus. Mifepristone is a synthetic steroid that blocks progesterone, the hormone necessary to maintain pregnancy. When progesterone is not available, the fertilized egg cannot stay attached to the uterus.

RU-486 is not used for contraception. It is available only by prescription. Before prescribing RU-486, a health care provider must do an HCG blood test and an ultrasound to confirm that a woman is pregnant, that she does not have an ectopic (tubal) pregnancy, and that the pregnancy is 49 days or less. RU 486 is approved for use up to the 49th day of pregnancy, or about seven weeks. When the pregnancy and date of pregnancy are confirmed, a woman takes one dose of mifepristone. Two days later, she takes a second drug, misoprostol, which causes the uterus to contract. Within six days to one week, the pregnancy is terminated.

A woman must return to her health care provider’s office to confirm that the pregnancy was terminated. If it was not, a surgical abortion must be performed. RU-486 is 92 percent effective in ending a pregnancy, if taken during the first seven weeks of pregnancy. Possible side effects of RU 486 include uterine cramps, fatigue, nausea and heavy bleeding.